1. Field of the Invention
The present invention relates to a method and an apparatus for recording and/or reproducing data in units of a predetermined size on an information storage medium, and the information storage medium.
2. Description of the Related Art
Recording and/or reproducing data on an information storage medium such as an HD-DVD, CD, or DVD is performed in units of a predetermined size. The units are referred to as recording unit blocks or reproducing unit blocks. An example of a recording unit block or a reproducing unit block is an error correction block for correcting errors occurring when data is recorded or reproduced.
Assuming that the size of an error correction block is 64 Kbytes, when data with a size of only 4 Kbytes, which corresponds not to the entire block but to part of the error correction block, is to be recorded, the remaining part (60 Kbytes) is filled with invalid values.
If the disc drive reads out the error correction block in order to reproduce the valid data occupying only part of the block, and performs error correction, error correction of codewords containing the meaningful 4 Kbyte data is possible, but error correction of codewords having the meaningless 60 Kbyte data is impossible and as a result it is determined that error correction is impossible in the entire error correction block. Since the disc drive cannot distinguish which part of the error correction block has valid data and which part is filled with invalid data, error correction or reproduction should be reattempted, or else the error correction block, despite the fact that it contains some valid data, is finally treated as an error block.